The Chesapeak and Ohio (C&O) Canal runs east-west through Georgetown, roughly paralleling M Street, from it's beginning at Rock Creek on the east to the Key Bridge and beyond for 185 miles. It is a reminder of Georgetown's past as a port. 

Georgetown was founded decades before the U.S.A. because it was the last navigable point on the Potomac. The Canal was built to extend freight transport to the west, over the Alleghenies. 

In landscape terms, although it is similar in scale to Georgetown's residential streets, its feeling is quite different. Its tranquil atmosphere is due mainly to being shielded from the noise of the city. In addition, it is, of course, filled with water (always a tranquil element).